Safety switch



c. 6, 1959 E, M, WARREN 2,907,853

` SAFETY SWITCH Filed Jan. 30, 1958 BY MM ATTORNEYS United States Patent F SAFETY SWITCH Estel M. Warren, Clinton, N.C. Application January 30, 1958, SerialvNo. 712,187

Claims. (Cl. 200-161)` The present invention relates to safety switches, and particularly safety switches used n motor vehicles.

The primary object of the invention is to provide a safety switch for motor vehicles which will break the ground circuit of the battery and simultaneously short out the positive side of the circuit.

Another object of the invention is to provide a safety i' Ice bolt of a motor vehicle to extend therethrough support-V ing the housing 11 and providing a ground connection therefor. The top wallr15 adjacent the end wall 14 1s f provided with a longitudinally extending slot 23 lfor Other'objects and advantages will become apparent the line 2 2 of Figure 3, looking in the direction, of

the arrows.

Figure 3 is a longitudinal vertical section taken along the line 3-3 of Figure 2, looking in the direction of the arrows.

Figure 4 is a View similar to Figure 3 illustrating the switch contacts in opposite position.

Figure 5 is a horizontal section taken along the line 5--5 of Figure 3, looking in the direction of the arrows.

Referring now to the drawings in detail wherein like reference characters indicate like parts throughout the several figures, the reference numeral 10 indicates generally a safety switch constructed in accordance with the invention.

The safety switch 10 includes a housing generally indicated at 11, and the housing 11 has a bottom wall 12, end walls 13, 14 formed integrally on opposite ends of the bottom wall, and a top Wall 15 arranged in parallel relation to the bottom wall 12 and welded to the end walls 13 and 14. The end wall 14 has an integral oliset extension 16 extending outwardly perpendicularly thereto. The top wall 15 has an integral aligned extension 17 extending outwardly beyond the housing 11.

A pair of side walls 18, 19 are arranged in contacting relation with the opposite sides of the end walls 13, 14, and opposite sides of the bottom Wall 12 in `spaced parallel relation to each other. The side walls 18 and 19 are each provided with inwardly extending tongues 20 integrally formed on the lower corners thereof and engaging within the housing 11 at the juncture of the end wall 13 and bottom wall 12 and the juncture of the end wall 14 and bottom wall 12. The tongues 20 engaging within the housing 11 assist in positioning the side walls 18 and 19 thereon.

Bolts 21 extend through the side walls 18 and 19 detachably securing them to the opposite sides of the purposes to be described. d

A ilat plate 24 is positioned within the housing 11 1n generally parallel relation to the bottom wall 12 and top wall 15 and is provided with a pair of tongues 25 extending through bores 26 formed in laterally spaced relation in the end wall 13.

The tongues 25 engage loosely in the bore 26 permitting the plate 24 to swing vertically thereabout. A cylindrical v copper contact 27 is provided with an integral reduced threaded extension 28 extending through a bore 29 in the center of the plate 24., The contact 27 has the upper end thereof domed at 30for reasons toV be assigned.

Av flexible copper Astrap31 has oneend thereof in contact with the plate 24'aud is engaged over the threaded extension 28 of the Contact .27., Ametal washer V32 is mounted on the threaded,l extension 28 andinter'posed between the contact 27 and the strap 31. Y v

A lock washer 33 and Vnut 34 are mo `Ited on the threadedextension 28on' the opposite side of the plate 24 locking the contact 27 to the plate 24. n p,

A coil spring 35 has one end in engagement withthe bottom wall 12 and theiother end in engagement with the nut 34 to normally bias the plate 24 in a direction toward the top wall 15. l

A bolt 36 exten' throughthe top wall 15 and secures the opposite end of the AStraplal thereto providing an electrical circuit 'between''the contact 27 and the top wall15. j y l L A generally cylindrical contact 37 is positioned below themtop' and' is provided'y with an upwardly extending threaded 'extension38' extending through' the top wall 15. The contact 37 is arranged in axial alignment with the contact 27, and the contacts 27, 37 are arranged for engagement at the uppermost position of the plate 24.

Insulating washers 39 are positioned on the threaded extension 38 on opposite sides of the top wall 15, and with an insulating bushing 40 surrounding the threaded extension 38 between the insulating washers 39, completely insulate the contact 37 from the top wall 15. Washers 41, lock washers 42, and nuts 43 all engage over the threaded extension 38 to lock the contact 27 to the top wall 15.

A cam plate 44 is positioned in the housing 11 and has a pair of tongues 45 depending from opposite sides of the lower end thereof engaging in notches 46 formed Y in opposite sides of the end of the plate 24 remote from the tongues 25. The cam plate 44 has a pair of shoulders 47 engaging the under side of the top wall 15 on opposite sides .of the slot 23 and has a shank 48 extending upwardly through the slot 23.

The upper end of the shank48 is formed into a loop 49 and has a Bowden wire 50 attached thereto. The Bowden wire housing 51 is secured to the offset extension 16 by means of a clamp 52 anda bolt 53. The Bowden wire 50 extends to the dashboard (not shown) of the motor vehicle and is arranged for movement under hand control.

A bolt 54 extends through the end wall 14 below the plate 24 and is insulated from the end wall 14 by insulating bushings 55. Lock nuts 56 secure the bolt 54 in the end wall 14. A resilient arm 57 is connected mechanically and electrically to thebolt 54 and extends upwardly to a point beneath the plate 24 for engagement therewith when the plate 24 is in its lowermost position.

contact 27 through the threaded extension 38 is connected Patented Oct. e, 1959Y to the ground side of the motor vehicle battery 58. The bolt 54 is connected to the positive side of a voltage regulator 59.

With the top wall connected to a grounded bolt (not shown) on a motor vehicle and vwith the cam plate 44 in the position illustrated in Figure' 4, the contacts 3.7 and 27 are engaged completing the ground circuit from the battery 58 to permit operation of the electric circuits of the motor vehicle. In the position illustrated in Figure 4, the resilient arm 57 is out of contact with the plate 24 so that the normal voltage regulator circuit is not affected thereby.

On leaving the motor vehicle, or inthe case of a wreck, fire, or short circuit, the B owden wire 50 is moved by any suitable means so as to move the cam plate 44 to the position illustrated in Figure 3, pressing the plate 24 downwardly against the tension of the spring 35 and breaking the engagement between the contacts 27, 37 to interrupt all electric circuits of the motor vehicle emanating from the battery 58. p

The downward movement of the plate 24 causes the plate 24 to engage the resilient arm 57 connecting the generator armature terminal of the voltage regulator 59 direct to ground through the plate 2,4, strap 31 and top wall 15. The grounding of the voltage regulator circuit will immediately stop the engine ofthe motor vehicle and will prevent the use'of an auxiliary battery to by-pass the safety switch 10. i

Having thus described the preferred embodiment of the invention, it should be understood that numerous structural modications and adaptations may be resorted to without departing from the scope of the appended claims.

What is claimed is:

l. A safety switch comprising a housing having a pair of spaced apart end walls connected at one end by a bottom wall and at the opposite end by a top wall, a pair of removable side walls releasably secured to opposite sides of said housing, a contact in said housingy securedy to and electrically insulated from said top wall, a plate extending between said end walls generally' parallel to said top wall, means on one end of said plate pivotally mounting said plate on one of said end walls for swinging movement toward said top wall, a second contact secured to said plate in aligned relation with said first contact with said contacts being adapted to engage on swinging movement of said plate, a spring extending between said bottom wall and said plate normally biasing said plate in the direction of said top wall, a cam plate extending from the opposite end of said plate toward said top wall, means on the lower end of said cam plate cooperating with means on the opposite end of said plate pivotally mounting said cam plate on said plate, said top wall having a longitudinal slot formed therein, a shank integrally formed on the upper end of said cam plate extending through said slot, said cam plate having the upper end thereof engaging the face of said top wall adjacent said plate and means engaging said shank for swinging said cam plate with respect to said plate to swing said plate away from said top wall against the tension of said spring.

2. A device as claimed in claim l wherein means are provided in said housing electrically connecting said second contact to said housing.

3. A device as claimed in claim 1 wherein the means pivotally mounting said plate on one of said end walls comprises a pair of tongues integrally formed on one end of said plate loosely engaging through bores formed in said one end wall.

4. A device as claimed in claim 2 wherein a resilient contact arm is positioned in and electrically insulated from said housing for engagement by said plate when swung to a position disengaging said first and second contacts.

5. A device as claimed in claim 1 wherein the means pivotally connecting said cam plate to the opposite end of said plate comprises a pair of depending tongues formed on the lower end of said cam plate engaging loosely in notches formedin the opposite end of said plate.

References Cited in the le of this patent UNITED STATES PATENTS 1,995,946 Schild Mar. 26, 1935 

